Chapter 12

Question 1

The basic structure of flavivirus

Answer 1

enveloped icosahedral with T=3 capsid, (+) ss-RNA with 1 C protein and 2 enveloped proteins (E and M)

Question 2

E is for

Answer 2

attachment and fusion

Question 3

Yellow fever virus (flavivirus)

Answer 3

monkeys and humans; hemorrhagic fever

Question 4

Dengue (types1-4) virus (flavivirus)

Answer 4

monkeys and humans; fever, arthralgia, rash, hemorrhagic fever

Question 5

West Nile virus (flavivirus)

Answer 5

birds and humans; fever, arthralgia, rash

Question 6

Bovine viral diarrhea (Pestivirus)

Answer 6

Ruminants; persistent infection, mucosal disease

Question 7

Hepatitis C (Hepacivirus)

Answer 7

humans, acute and chronic hepatitis

Question 8

mosquitoes are anthropod vector to

Answer 8

yellow fever, dengue, and west nile viruses

Question 9

yellow fever virus is controlled via

Answer 9

vaccination with live attenuated by Theiler

Question 10

Dengue virus originates in

Answer 10

tropics

Question 11

West Nile virus is in

Answer 11

North America since 1999

Question 12

Yellow fever virus has three stages in symptom progression

Answer 12

1) high fever, muscle pain, headache, and severe vomiting; 2) latent stage of fever dissipating; 3) repeat of original symptoms with more severity

Question 13

the genome structure of the flavivirus is

Answer 13

linear (+) ss-RNA with 5’ cap structure and no poly(A) tail

Question 14

the genome structure of the pestivirus and hepacivirus is

Answer 14

no 5’ cap IRES instead and no poly(A) tail

Question 15

yellow fever genome has

Answer 15

structural C, prM, E; non-structural NS1, 2A, 2B, 3, 4A, 4B, 5

Question 16

the genome is taken steps of

Answer 16

from one ORF to one polyprotein to 10 mature proteins

Question 17

the structural proteins of YFV are

Answer 17

anchC -> C, prM -> M, E

Question 18

anchC is

Answer 18

“anchored” capsid protein. precursor to capsid protein; signal sequence inserted in membrane is cleaved by viral proteinase

Question 19

C’s function is

Answer 19

encapsidation of genome RNA

Question 20

prM’s function is

Answer 20

binding to E glycoprotein, inhibiting membrane fusion during transit through Golgi. cleaved to produce mature M protein, releasing pr.

Question 21

M is

Answer 21

small envelope glycoprotein. Function in the mature virion is unknown.

Question 22

E is

Answer 22

major envelope glycoprotein. receptor binding, fusion of virus envelope with cell membrane

Question 23

viral protease “NS2B-NS3” cleaves

Answer 23

c from AncC

Question 24

cellular signal peptidase cleaves

Answer 24

between AncC and M, M and E, E and NS1

Question 25

cellular furin protease cleaves

Answer 25

prM-E to pr+M and E-E for maturation process

Question 26

E protein is

Answer 26

type-1 transmembrane that forms head-to-tail dimer

Question 27

E-protein dimer turns into trimer before

Answer 27

fusion

Question 28

Domain III and I have

Answer 28

N and C terminus, and is for attachment

Question 29

fusion protein is located at

Answer 29

fusion peptide near domain II and III, which is hydrophobic and ph-dependent

Question 30

the nonstructural proteins of YFV are

Answer 30

NS1, 2A, 2B, 3, 4A, 4B, 5

Question 31

NS1 is

Answer 31

RNA replicase component, possibly involved in replication complex formation

Question 32

NS2A is

Answer 32

RNA replicase complex, either direct role in replication or targeting replicase complex to membranes

Question 33

NS2B is

Answer 33

part of viral proteinase that cleaves viral polyprotein

Question 34

NS3 is

Answer 34

viral serine proteinase involved in polyprotein cleavage; RNA replicase component; nucleoside triphophatase and helicase activites

Question 35

NS4A is

Answer 35

RNA replicase component, may recruit NS1 and other proteins into replicase complex

Question 36

NS4B is

Answer 36

unknown for role. Associated with membranes in cytoplasm; may translocate to nucleus

Question 37

NS5 is

Answer 37

RdRp; methyltrasnferase that methlylates cap structure

Question 38

RNA replicase complex assembles on

Answer 38

outer ER membranes

Question 39

After endocytosis, E-E turns into

Answer 39

E-E-E

Question 40

Virus fusion and disassembly is depended on

Answer 40

the low pH within a late endosome, promoting the fusion of viral and cellular membrane by the E protein

Question 41

RNA is released to

Answer 41

the cytoplasm

Question 42

protein translation of the RNA leads to

Answer 42

the establishment of membrane-bound RNA replication factories

Question 43

membrane-bound RNA replication factories are spatially linked to

Answer 43

sites of assembly and budding of immature virus on membrane of the ER

Question 44

the immature virus is

Answer 44

glycosylated and traverses the secretory network

Question 45

in the trans-Golgi network, the low pH promotes

Answer 45

the folding of the spike-containing immature particles into the semi-mature state and permits the cleavage of prM by host furin protease

Question 46

release of the virions into the ECM results in

Answer 46

release of the pr protein and a fully infectious mature virions